Terminal screw lug



June -6, i939. 2,161,249 AFB. DIBNER, NOW BY JUDICIAL CHANGE OF NAME B.DIBNER TERMINAL SCREW LUG Filed July 9, 1935 INVENTOR ATTORNEYS PnemedJue-e, less I r j 2,161,249

; umrsn sTA'rss [PATENT OFFICE. annals mammal. scnaw we AbrahamBernard-Dibner, Peekskill, N. YJ, now

by judicial change of name Bern Dlbner, assignor to Burndy Engineering00., Inc., New York, N. Y., acorporation of'New York Application July 3,1935, Serial No. 30,429 9 claims. (01.173-269) This invention relates toterminal lugs for of my invention will be described in detail in theelectric wires, cables and the like, and refers specification as itproceeds. particularly to the type in'which the end of a In theaccompanying drawing forming part wire or cable is gripped in a screwoperated hereof:

clamp. r i Fig. 1 is a side elevation of a terminal lug 5 The mainobject of my invention is to provide made according to the invention andembodying -a simple and eflicient terminal lug of the solderthe mainprinciples thereof, an end of a cable less type which is time saving inuse and very beingshown in position in the lug. easy to apply. a Fig. 2is a top plan view of the same terminal Another object is to provide aterminal lus lug.

' of the characterindicated-which is very easy Fig. 3 is a section of amodification of the and economical to manui'acturejand thereforeterminal lug. readily-placed upon the market. f Fig. 4-is another viewof the device of Fig. 1 It is a very important object to have aterasseen from the right, the end of a large' solid minal lug of thischaracter provided with a cable being shown in position and in section.15 clamping screw or bolt which is capable of ex- Fig, 5 is a similarview as in Fig. 4, exceptthat ertlng considerable clamping pressureupon' the' the overlapping top portion is attached together end of anelectric wire or cable, even of the as by welding or soldering andwherein the end multiple strand type, so that the end of the wire of amultiple strand cable of relatively smaller m or cable is securely heldand the lug thereby fixed size is shown than that in Fig. 4 and.generally upon the same. corresponding with the cable end of Figs. 1and 2. A further object is to provide such a terminal Fig. 6 is a planview of a blank of sheet metal lug'with a protective pressure bar whichis autofrom which the main body of either of the lugs matically retainedin assemblage with the lug of the preceding views may be made. when onceplaced in position therein-and serves Fig, 7 is a section similar toFig. 3, illustratf' to protect the end of the wire or cable from muing.modification of the terminal lug as well as tilation by the clamp nscrew 0f t e 8- of the pressure bar and set screw. It is also ,an,object to produce 9, lug of this Fig. 8 is a top plan view of thepressure bar the whi h is pted foruse with'a whole range used inconjunction with the set screw or bolt of sizes; of wires or cables,without requiring a] of Fig. 3. diiferent size of lug for each size ofwire or par- Fig. 9 is a side elevation of the same pressure ticularthought or precaution but merely relegatbar. ing the matter of cablesize -to be fitted to a "Throughout the views the same referencenusimple question of adjustment. merals indicate the same or like parts.Hereto- It is eve an je e e to have -1118 which, fore the great majorityof cable lugs were inby virtue of its structural form automaticallystalled on the ends of wires and cables by soldercenters the end of awire in a position wherein ing th same on said wires and cables,necesthe c p Pressure applied e n i qua y sarlly involving the use ofcumbersome and nuexerted in a balanced manner was to avoid inmeroustools, as well as hazardous equipment, jury to the wire during theapplication of the not to mention that often considerable time lugthereto. I would also be consumed in making such soldered 40 Anotheradditional object is to so construct a installation. Naturally thenecessity has been te min l ls f this p h w n h lampfelt for a moreconvenient type of terminal lug ing screw or bolt is screwed down upon awire installation and as a result certaincable lugs end, its pressuretends to increase the friction have appeared upon'the market which avoidbetween the threads in the lug proper-and those the use of solder butthey usually introduce new of the screw in order to cause, the screw tobe problems and are also not simple in construc- .very firmly gripped inthe lug so as to remain tion and also sacrifice some desirable featuresecurely in any attained position of adjustment. which'was actuallypresent in the old type of It may be mentioned '8 n of the objects ofsoldered lug installation such as direct and rigid this invention thatthe lug proper embodying the connections and security thereof. mainfeatures thereof. may be made from In orderto avoid allthe'disadvantages and instamped blanks of sheet metal bent into finalconveniences invoived'in the operation of solderform and properlythreaded toreceive the clamp in'g terminal lug installations accordingto the ing bolt or screw. old methods and also the use and evenconstruc- It Further objects and the several advantages tion of thesolderless types and particularly with 5 2 the foregoing objects in viewthe present invention is designed, and primarily consists of a one pieceor unitary terminal lug body which may be attached directly to a panelboard and to which the end of a cable or wire may be directly secured bymeans which will presently be described in detail.

Hence, in the practice of my invention a terminal lug body generallyindicated at l, oi. metal such as copper or a suitable alloy, has a fiatlug portion 2 having an aperture 9 for a screw or bolt by which tosecure the same to a connection on a switchboard or panel, etc., atubular body portion 3 which is V shaped at the bottom as shown at 4 andhas the two upper ends 5 and 6 overlapping each other. Through theoverlapping members 5 and 5 a threaded hole extends into which a setscrew or bolt 1 is fitted so that turning of the screw will cause thelower end thereof to approach or recede from the lower v shaped bottom 4of the tubular portion 3 of said lug. If the end l2 of a cable i3 isthrust into the tubular portion of the lug and the screw 7 turned byfitting a screwdriver into its upper slot l I the screw will descendupon the cable end. and clamp the same between said screw and said Vshaped bottom 6 in a vise like grip. As will presv ently be described,another means may be used to secure the overlapping ends 5 and 6together.

' follow the screw whether However, in order to prevent the lower end ofthe screw from grating or grinding directly upon the wire or the cable,it is preferred to intro duce a pressure bar, one form of which is shownat I as shown in Figs. 8 and 9, so that said pressure bar is interposedbetween the end of the screw and the bare end of the cable. The

pressure bar in this form is bent doubleso'that the lower portion 22 hasthe upper bifurcated portions l9-l9 overlying the same with a slot IBbetween the bifurcations enlarged at it to fit the neck it of theset'screw. When the set screw 1 has been screwed part of the way intothe lug and the pressure bar placed with the bifurcations l9-i9straddling the neck it of the screw 1, it is but necessary to force thepressure bar home and the bifurcations will ride past the neck of thescrew and finally seat in the enlarged portion 20, after which thepressure bar will be retained by flange or fiat head it upon said setscrew, with the result that the pressure bar will the latter is screwedwhile the pressure bar the screw upwardly or downwardly, in turn willprevent loss Or removal of from the terminal lug.

An alternative device with integrally connecting overlapping ends, asshown in Fig.- 3, con-= sists in drifting metal downwardly as at a fromthe upper member 6 through member and then forming the screw thread insaid drifted metal 8, the latter metal extending even past the lowersurface of overlapped member 5' so that the screw thread is longer thanif it merely passed through the two thicknesses of the overlappingmembers A double gain is thus attained,

- namely, that the length or the screw thread is increased and bothoverlapped members are as rigidly united. as-though riveted together.The

parts 3', 4', 5', 8 and 9' correspond to parts 3, 4, '5, 6 and 9,respectively of the other views.

'. It is nevertheless possible to omit drifting of the metal from one ofthe overlapped-members through the other and instead leaving theoverlapping members free with the screw passing simply through thethreaded thicknesses of each,

upon the screw shown er diameter is similarly gripped, the screw andpressure bar in this case being necessarily in lower positions. However,it is sometimes desirable to provide a clearance in the pressure bar forthe head or flange I5 upon the lower end of set 'screw I and in order toafford such clearance,

an aperture 2| as shown in Fig. 8 is punched in the bottom portion 22 ofthe pressure bar so that even this clearance serves as an additionalretaining means for the pressure bar upon the set screw, because thehead or flange in Fig. 3, will tend to seat or spring into place in saidaperture when assembling the pressure bar upon the screw. Naturally thethickness of the lower portiorrZZ of the pressure bar is at least equalto the thickness of flange l5 of the screw and the latter may even beless than the gauge of said lower portion 22. Manifestly, when a cableor wire is placed in position in the tubular portion 3 of the terminallug and the pressure bar lowered upon the same by means of the setscrew, the V shapedbottom will positively center the end of the cableexactly below said set screw so that all side strainsand unequalpressures with resulting injury to the cable are avoided, but thepressure exerted will nevertheless theoretically tend to resilientlyopen the -V shaped bottom t and spread the sides of the tubular portion3 and simultaneously tend to pull .apart overlapping members 5 a and 6of thedevice illustrated in Figs. 4 and '1,

so as to exert a shearing strain upon the set screw. This will,'ofcourse, not shear the screw but will instead cause the threaded portionsof members 5 and 6 to almost lock upon' the screw by a very' greatresulting friction so that the screw is held fast without any danger ofunscrewing or releasing the pressure bar from the cable. This very greatresulting friction is caused by the substantially rigid body, which isbut slightly deflected even when the mechanical means used to applypressure to the conductor is tightened, in the modification where theoverlapping portions of sheet metal are not interlocked.

- The blank from which the body of the connector of Figs. 3 and 41s madeis shown in Fig. 6. The lug 2 is integrally formed with the bottomsection 4, the side walls, and the overlapping ends 5 and 6. The bottomt is shaped to form av V and the sides and overlapping ends form thetubular body 3.

When forming the body portion for the device shown in Fig. 1, a holeshown incircular broken lines in member 6 of Fig. 6 is punched in theends 5 and 6, which holes are subsequently tappedv for the screw 1.

When theblank is used for the modification shown in Fig. 3, a hole shownin circular broken lines in member 8, of Fig. 6, is punched in end 6only and a larger hole, shown in circular broken lines in member! ispunched so that the metal of the smaller sized hole may be drifteddownward, as shown in Fig. 3 to lock the overlapping edges together andprovide a longer length of metal, as indicated at 8, which issubsequently threaded for the screw 1, as previously explained.

It is obviously quite possible to grip more than one cable or wire inthe lug because two or three the pressure bar is the V shaped flat lugportion 23 corresponds to the previously 1 or even more ends oi cables,wires or similar conductors can be connected to the lug simultanemayconceivably avoid ously, as this sometimes necessity for otherconnections.

A modification oi the pressure barprimarily is shown in Fig. 7, whereinaihorizontal strip portion" is disposed intermediate overlapping end.portions 28 and 28 oi the tubular portion 24 of the lug, 'while thebent downwardly in arcuate form beneath the set screw 3| and is intendedto be constructed of resilient material so that the arcuate portion IIIwill follow. the screw upwardly when the latter is unscrewed in anupward direction and will, of course, be pushed down by the screw intoany downwardly projected position when the screw is screwed down towardbottom 26 of the samelug.' The described lug portion 2, whilethe Vshaped bottom 26 is serrated or provided with teeth as in- .Qdicated atso as to more firmly grip .an end the lug. vOi course, the serrations ofa cable when the latter is to besecured in may ,be the main that'theposition due to the fact passes through portion 21 01' omitted ifdesired as they do not form feature 01' the invention. It is evidentpressure bar remains in that set screw 3i the same, although in thisform of the mg the so I I other'aperture for compressing 'a cable longiset'screw is 'mushroomed at its lower end 42 to prevent it from beingremoved from the lug by unscrewing the same. The-mushroomed lower end"thus serves as ameans for retaining the set screw in assembledcondition with the lug in this form, nevertheless a set screw 1 of theform shown in Fig. 3 can also be used with a clip or split washer (notshown) forced into position about the neck It in known manner so as topermanently retain the set screw in the lug it so. desired.

In connection with the set screw it is obvious that "any kind oflscrewalready known may be used and instead of having a rounded upper endmerely provided with a slot II for receiving the screw driver, the screwmay be surmounted by a square or hexagonal head, the size of such headbeing of no great importanceand the shape thereof naturallyi'orming noactual part of the invention.

In view of the foregoing description and the accompanying figures of thedrawing which have now been disclosed, it is obvious that furthervariations may be resorted to and parts may be used without otherswithin the spirit and scope or the invention.

Having now fully described my invention, I

claim .a T-shaped blank of sheet metal, the side wings v bent into atubular shaped body having a bottom and side walls, and overlappingapertured ends forming the top portion, the leg of the T forming a flatterminal place, and a clamping screw threadedly engaging at least one ofthe apertures in ends and passing through the tudinally into'theconnector body.

2. An-electrical terminal for electric cables comprising-a substantiallyrigidbody made from a T-shaped blank 01' sheet metal, the side'wings lbent into a tubular shaped body having a tom and side walls, andoverlapping, attac ed,

apertured ends-forming the top portion, the leg of the 'T forming aiiat'terminal plate, and a remaining portion 3| of a clamping screwthreadedly engaging at least one of the apertures in the attached endsand passing through the other aperture for compressing a cablelongitudinally into the connector body 3. electrical terminal forelectric cables comprising a substantially rigid body made from aT-shaped blank of sheet metal, the side wings body, said interlockconsisting of metal drifted from one overlapping end into the apertureof the other.

4. A terminal lug for electric wires, cables and the like, forming aninseparable assembled'unit and comprising in combinatiom-a U shapedmember oi metal having a flat lug portion integrally connected to thebottom portion thereof in parallelism with the axis of said U shapedmember and having the upper ends 01' the same bent over each other so asto mutually overlap, and an ad- Justable clamping screw extendingthrough both 01 said overlapping upper ends ofsaid U shaped membertoward the member with said lower portion formed into a V shaped bottommerging with said flat lug portion and the sides of said U shaped memberterminating at their upper ends in a pair 01' bent mutually overlappingportions, and an adjustable clamping screw extending through both orsaid overlapping'portions of said U shaped member toward said V shapedbottom in order to cause said bottom to spread or open and saidoverlapping portions to tend to separate and exert a transverse shearingstrain upon said screw when the latter is brought down under pressureupon the end of a cable within said U shaped member and thereby tend toautomatically retain the screw by friction in any attained position uponsaid cable.

' 6. A terminal lug according to claim 4, wherein the lower end of theclamping screw is rotatably connected to a'removable pressure bardisposed and guided between the sides 0! the U shaped member and ismovable upwardly and downwardly with the screw when the latter isrotated, one portion or said pressure bar being bifurcated and saidbifurcated portion straddling said bottom of the latter in order tocause said bottom to spread or open and saidstraddling said clampingscrew above said flange.

9. A terminal lug according to claim 5. wherein the clamping screw has aflange upon the lower end thereof and a removable pressure bar ismounted upon and retained by said flange and is disposed and guidedbetween the sides of the U shaped member so as to be upwardly ordownwardly movable between said sides upon rotation oi said screw oneportion 01. said pressure bar being bifurcated and saidbiiurcated'portion straddling said clamping screw above said flange.

ABRAHAM BERNARD DIBNER.

